It may be difficult for a user to detect inhomogeneities in images, for example inspection images, particularly when the user has to visualize a great number of images. Also it may be difficult to detect inhomogeneities in images having a given level of contrast. These difficulties may represent a threat to security, as inhomogeneities in images may correspond to hidden objects, such as weapons or dangerous material.
In the Figures like reference numerals are used to indicate like elements.